Sn-Doped Hard Carbon As a Practical Anode for Sodium-Ion Batteries

Rechargeable sodium-ion batteries (SIBs) are attracting extensively interest as a promise post lithium-ion batteries (LIBs). Amongst all the reported anode materials, there is no doubt that hard carbon (HC), equivalently to graphite in LIBs, is the most potential material to realize practical commercialization. The main challenge is its low specific capacity (~280 mAh g^-1) [1]. Another potential anode, tin, adversely is capable to deliver high capacity while very poor cycling stability [2]. Therefore, doping small amount Sn into HC is expected to achieve higher capacity and maintain prolonged cycling life as well.

Herein, we prepare Sn-doped HC anode by evaporating rotation method, with SnCl₂ and sucrose as raw sources. The obtained black powered is annealing by tube furnace under Ar atmosphere. The designed weight ratio of Sn in the mixture is 15 %. As shown in Figure 1, Sn-doped HC shows much better electrochemical performance than HC, delivering a higher capacity of ~350 mAh g^-1over 70 cycles. Furthermore, different Sn-doped amount and various electrolytes would be applied in the future, aiming to reach the optimal performance of this anode. 

[1]S.Komaba, W. Murata, T. Ishikawa, N. Yabuuchi, T. Ozeki, T. Nakayama, A. Ogata, K. Gotoh, K. Fujiwara. Adv. Funct. Mater. 2011, 21, 3859-3867.

[2] T. Yamamoto, T. Nohira, R. Hagiwara, A. Fukunaga, S. Sakai, K. Nitta, S. Inazawa. J. Power Sources 2012, 217, 479-484. 

Figure.1 Cycling performances of Sn-doped HC and HC with 1.0 M NaClO₄ in propylene carbonate (PC) / ethylene carbonate (EC) 1:1 (weight ratio).